Three-dimensional printing

ABSTRACT

According to examples described herein, methods, compositions, and parts comprising an antistatic agent are described. According to one example, a method of three-dimensional printing can comprise: (i) a layer of build material being deposited; (ii) a first fusing agent being selectively applied on the build material, wherein the first fusing agent can comprise at least one first antistatic agent; and (iii) repetition of (i) and (ii) at least once to form a core of a three-dimensional part.

BACKGROUND

Three-dimensional (3D) printing can be an additive printing process usedto make three-dimensional object(s) or part(s) from a digital model. 3Dprinting is often used in rapid product prototyping, mold generation,and mold master generation. Some 3D printing techniques are consideredadditive processes because they involve the application of successivelayers of material. This is unlike machining processes, which tend torely upon the removal of material to create the final part. Materialsused in 3D printing tend to use curing or fusing, which for somematerials may be accomplished using heat-assisted extrusion orsintering, and for other materials may be accomplished using digitallight projection technology.

BRIEF DESCRIPTION OF THE DRAWING

Features of examples of the present disclosure will become apparent byreference to the following detailed description and drawings, in whichlike reference numerals correspond to similar, though perhaps notidentical, components. For the sake of brevity, reference numerals orfeatures having a previously described function may or may not bedescribed in connection with other drawings in which they appear.

FIG. 1 shows an example of a simplified isometric view of an examplethree-dimensional (3D) printer for generating, building, or printingthree-dimensional parts.

FIG. 2 shows an example three-dimensional printed part.

FIGS. 3 and 4 each respectively show flow diagrams of example methods ofthree-dimensional printing.

FIG. 5 is an example graph showing bulk resistivity per amount ofantistatic agent.

FIG. 6 is an example graph showing surface resistivity per percentsolids.

FIG. 7 is an example graph showing surface resistivity per percentsolids.

DETAILED DESCRIPTION

For simplicity and illustrative purposes, the present disclosure isdescribed by examples. In the following description, numerous detailsare set forth in order to provide a thorough understanding of thepresent disclosure. It will be apparent, however, that the presentdisclosure may be practiced without limitation to these details in everyexample. In other instances, some methods and structures have not beendescribed in detail so as not to unnecessarily obscure the presentdisclosure.

To reduce or eliminate build-up of static charge, plastic/polymericparts/objects can require additives due to their insulating nature.Static build-up in polymeric parts/object is typically a result of thetriboelectric effect, in which frictional contact between surfaces leadsto electron transfer. If the polymeric part/object surface cannotdissipate the charge, an electrostatic discharge (ESD) event can result.In manufacturing settings, ESD events can negatively affect production,yield, cost, and/or product reliability, among other things. This isusually due to the potential for ESD to cause damage to sensitivecircuitry and/or ignite flammable materials.

Similarly, in three-dimensional printing, ESD can similarly occur andresult in polymeric parts/objects printed via three-dimensionalprinting. ESD in a 3D printed part can be reduced by imparting staticdissipative or conductive properties to the part.

There is a need for methods and compositions to print 3D parts withreduced and/or no ESD. There is also a need for methods and compositionsto reduce and/or eliminate ESD.

Disclosed herein are 3D printing methods, 3D printers implemented by the3D printing methods, 3D printing compositions, and agents. A 3D part maybe printed, formed, or otherwise generated onto a build area platform.The 3D printer may also include a spreader to spread a layer of a buildmaterial onto the build area platform, and a printhead to selectivelydeposit the agent. The 3D printer may form successive layers of thebuild material, which may be spread and may receive the agent. As usedherein “3D printed part,” “3D part,” “3D object,” “object,” or “part”may be a completed 3D printed part or a layer of a 3D printed part.

In one example, disclosed is a method of three-dimensional printingcomprising: (i) depositing a layer of build material; (ii) selectivelyapplying a first fusing agent on the build material, wherein the firstfusing agent comprises at least one first antistatic agent; and (iii)repeating (i) and (ii) at least once to form a core of athree-dimensional part.

The method further comprises (iv) applying a second fusing agent and afirst detailing agent on the core of the three-dimensional part to forman inner shell at least partially enclosing the core, wherein the firstdetailing agent comprises at least one second antistatic agent; and (v)applying a second detailing agent on the inner shell, wherein the seconddetailing agent is free of any near infrared absorbing compound.

The second fusing agent further comprises at least one second nearinfrared absorbing compound; and the second detailing agent furthercomprises at least one third antistatic agent.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent are different; and the first near infrared absorbingcompound and the second near infrared absorbing compound are different.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent are the same, and the first antistatic agent, thesecond antistatic agent, and the third antistatic agent areindependently selected from the group consisting of Li₂NiBr₄, Li₂CuCl₄,LiCuO, LiCu₄O(PO₄)₂, LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₆H₅COOLi,LiBr, Li₂CO₃, LiCl, C₆H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄, Li₂SO₄,Li₂B₄O₇, LiAlCl₄, AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄,LiAg₂V₄O₁₁, LiSVO, LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄, LiCuS,LiPbCuS, LiFeS, LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂,Li/Al—V₂O₅, lithium bis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂,LiAsF₆, LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₉),LiOSO₂CF₃, and combinations thereof.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent are independently selected from the group consisting ofa salt of an alkali or alkaline earth metal selected from the groupconsisting of quaternary amines, chlorates, phosphates, carbonates,borates, phosphonates, sulfates, acetates, citrates, perchlorates, andcombinations thereof.

The first antistatic agent is present in an amount of from about 0.1 wt.% to about 10 wt. % based upon a total weight of the first fusing agent;the second antistatic agent is present in an amount of from about 0.01wt. % to about 7 wt. % based upon a total weight of the first detailingagent; and the third antistatic agent is present in an amount of fromabout 0.01 wt. % to about 7 wt. % based upon a total weight of thesecond detailing agent.

The first fusing agent further comprises water, at least one organicsolvent, at least one surfactant, and at least one biocide.

In an example, disclosed is a three-dimensional printed part comprising:a core comprising a build material selected from the group consisting ofpolyamides, polyethers, polyethylenes, polyethylene terephthalates,polystyrenes, polyacetals, polypropylenes, polycarbonates, polyesters,thermoplastic polyurethanes, and combinations thereof, and at least onefirst antistatic agent.

The three-dimensional printed part can further comprise: an inner shellat least partially enclosing the core, the inner shell comprising thebuild material and (i) at least one second antistatic agent or (ii) freeof any antistatic agent; and an external shell at least partiallyenclosing the inner shell, the external shell comprising the buildmaterial and (i) at least one third antistatic agent or (ii) free of anyantistatic agent.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent can be the same or different. The first near infraredabsorbing compound and the second near infrared absorbing compound canbe the same or different.

The first antistatic agent, the second antistatic agent, and thirdantistatic agent are thermally stable at a polymer melt processingtemperature. The first antistatic agent, the second antistatic agent,and the third antistatic agent are independently selected from the groupconsisting of Li₂NiBr₄, Li₂CuCl₄, LiCuO, LiCu₄O(PO₄)₂, LiSOCl₂,LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₆H₅COOLi, LiBr, Li₂CO₃, LiCl,C₆H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄, Li₂SO₄, Li₂B₄O₇, LiAlCl₄,AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁, LiSVO,LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄, LiCuS, LiPbCuS, LiFeS,LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅,lithium bis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂, LiAsF₆,LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₉),LiOSO₂CF₃, and combinations thereof.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent are independently selected from the group consisting ofa salt of an alkali or alkaline earth metal selected from the groupconsisting of quaternary amines, chlorates, phosphates, carbonates,borates, phosphonates, sulfates, acetates, citrates, perchlorates, andcombinations thereof.

The first antistatic agent is present in an amount of from about 0.1 wt.% to about 10 wt. % based upon a total weight of the core; the secondantistatic agent is present in an amount of from about 0.01 wt. % toabout 7 wt. % based upon a total weight of the inner shell; and thethird antistatic agent is present in an amount of from about 0.01 wt. %to about 7 wt. % based upon a total weight of the outer shell.

The build material is polyamide-12, polyether block amide, or acombination thereof.

In one example, disclosed is a method of three-dimensional printingcomprising: (i) depositing a layer of build material; (ii) selectivelyapplying a first fusing agent comprising: at least one antistatic agenton the build material, at least one first near infrared absorbingcompound, at least one surfactant, at least one organic solvent, andwater; (iii) repeating (i) and (ii) at least once to form a core of athree-dimensional part; (iv) applying a second fusing agent and a firstdetailing agent on the core of the three-dimensional part to form aninner shell at least partially enclosing the core, wherein the secondfusing agent comprises at least one second near infrared absorbingcompound, and wherein the first detailing agent is free of anyantistatic agent; and (v) applying a second detailing agent on the innershell to at least partially enclose the inner shell and form an externalshell, wherein the second detailing agent is free of (a) any nearinfrared absorbing compound and (b) any antistatic agent.

With reference first to FIG. 1, there is shown a simplified isometricview of an example 3D printer 100 for generating, building, or printingthree-dimensional parts. It should be understood that the 3D printer 100depicted in FIG. 1 may include additional components and that some ofthe components described herein may be removed and/or modified withoutdeparting from a scope of the 3D printer 100 disclosed herein. It shouldalso be understood that the components of the 3D printer 100 depicted inFIG. 1 may not be drawn to scale and thus, the 3D printer 100 may have adifferent size and/or configuration other than as shown therein.

The 3D printer 100 may be used to form a three-dimensional printed part40 shown in FIG. 2 comprising: a core 10 comprising a build materialselected from the group consisting of polyamides, polyethers,polyethylenes, polyethylene terephthalates, polystyrenes, polyacetals,polypropylenes, polycarbonates, polyesters, thermoplastic polyurethanes,and combinations thereof, and at least one first antistatic agent.

The three-dimensional printed part can further comprise: an inner shell20 at least partially enclosing the core 10, the inner shell 20comprising the build material and (i) at least one second antistaticagent or (ii) free of any antistatic agent; and an external shell 30 atleast partially enclosing the inner shell 20, the external shell 30comprising the build material and (i) at least one third antistaticagent or (ii) free of any antistatic agent.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent can be the same or in someexamples, they can be different.

In some examples, the first antistatic agent, the second antistaticagent, and third antistatic agent can be thermally stable at a polymermelt processing temperature.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent can be independently selected fromthe group consisting of Li₂NiBr₄, Li₂CuCl₄, LiCuO, LiCu₄O(PO₄)₂,LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₅H₅COOLi, LiBr, Li₂CO₃, LiCl,C₅H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄, Li₂SO₄, Li₂B₄O₇, LiAlCl₄,AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁, LiSVO,LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄, LiCuS, LiPbCuS, LiFeS,LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅,lithium bis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂, LiAsF₆,LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₉),LiOSO₂CF₃, and combinations thereof.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent can be independently selected fromthe group consisting of a salt of an alkali or alkaline earth metalselected from the group consisting of quaternary amines, chlorates,phosphates, carbonates, borates, phosphonates, sulfates, acetates,citrates, perchlorates, and combinations thereof.

In some examples, the first antistatic agent can be present in an amountof from about 0.1 wt. % to about 10 wt. % based upon a total weight ofthe first fusing agent, or in an amount of from about 0.5 wt. % to about9 wt. % based upon a total weight of the first fusing agent, or in anamount of from about 1 wt. % to about 8 wt. % based upon a total weightof the first fusing agent, or in an amount of from about 2 wt. % toabout 7 wt. % based upon a total weight of the first fusing agent, or inan amount of less than about 10 wt. % based upon a total weight of thefirst fusing agent, or in an amount of less than about 9 wt. % basedupon a total weight of the first fusing agent, or in an amount of lessthan about 8 wt. % based upon a total weight of the first fusing agent,or in an amount of less than about 7 wt. % based upon a total weight ofthe first fusing agent, or in an amount of less than about 6 wt. % basedupon a total weight of the first fusing agent, or in an amount of lessthan about 5 wt. % based upon a total weight of the first fusing agent,or in an amount of less than about 4 wt. % based upon a total weight ofthe first fusing agent, or in an amount of greater than about 0.1 wt. %based upon a total weight of the first fusing agent, or in an amount ofgreater than about 0.5 wt. % based upon a total weight of the firstfusing agent, or in an amount of greater than about 1 wt. % based upon atotal weight of the first fusing agent, or in an amount of greater thanabout 2 wt. % based upon a total weight of the first fusing agent, or inan amount of greater than about 3 wt. % based upon a total weight of thefirst fusing agent, or in an amount of greater than about 4 wt. % basedupon a total weight of the first fusing agent, or in an amount ofgreater than about 5 wt. % based upon a total weight of the first fusingagent, or in an amount of greater than about 6 wt. % based upon a totalweight of the first fusing agent, or in an amount of greater than about7 wt. % based upon a total weight of the first fusing agent, or in anamount of greater than about 8 wt. % based upon a total weight of thefirst fusing agent, or in an amount of greater than about 9 wt. % basedupon a total weight of the first fusing agent.

In some examples, the second antistatic agent is present in an amount offrom about 0.01 wt. % to about 7 wt. % based upon a total weight of thefirst detailing agent, or in an amount of from about 0.1 wt. % to about6 wt. % based upon a total weight of the first detailing agent, or in anamount of from about 1 wt. % to about 5 wt. % based upon a total weightof the first detailing agent, or in an amount of from about 2 wt. % toabout 4 wt. % based upon a total weight of the first detailing agent, orin an amount of less than about 7 wt. % based upon a total weight of thefirst detailing agent, or in an amount of less than about 6 wt. % basedupon a total weight of the first detailing agent, or in an amount ofless than about 5 wt. % based upon a total weight of the first detailingagent, or in an amount of less than about 4 wt. % based upon a totalweight of the first detailing agent, or in an amount of less than about3 wt. % based upon a total weight of the first detailing agent, or in anamount of less than about 2 wt. % based upon a total weight of the firstdetailing agent, or in an amount of less than about 1 wt. % based upon atotal weight of the first detailing agent, or in an amount of greaterthan about 0.01 wt. % based upon a total weight of the first detailingagent, or in an amount of greater than about 0.1 wt. % based upon atotal weight of the first detailing agent, or in an amount of greaterthan about 1 wt. % based upon a total weight of the first detailingagent, or in an amount of greater than about 2 wt. % based upon a totalweight of the first detailing agent, or in an amount of greater thanabout 3 wt. % based upon a total weight of the first detailing agent, orin an amount of greater than about 4 wt. % based upon a total weight ofthe first detailing agent, or in an amount of greater than about 5 wt. %based upon a total weight of the first detailing agent, or in an amountof greater than about 6 wt. % based upon a total weight of the firstdetailing agent.

In some examples, the third antistatic agent is present in an amount offrom about 0.01 wt. % to about 7 wt. % based upon a total weight of thesecond detailing agent, or in an amount of from about 0.1 wt % to about6 wt. % based upon a total weight of the second detailing agent, or inan amount of from about 1 wt. % to about 5 wt. % based upon a totalweight of the second detailing agent, or in an amount of from about 2wt. % to about 4 wt. % based upon a total weight of the second detailingagent, or in an amount of less than about 7 wt. % based upon a totalweight of the second detailing agent, or in an amount of less than about6 wt. % based upon a total weight of the second detailing agent, or inan amount of less than about 5 wt. % based upon a total weight of thesecond detailing agent, or in an amount of less than about 4 wt. % basedupon a total weight of the second detailing agent, or in an amount ofless than about 3 wt. % based upon a total weight of the seconddetailing agent, or in an amount of less than about 2 wt. % based upon atotal weight of the second detailing agent, or in an amount of less thanabout 1 wt. % based upon a total weight of the second detailing agent,or in an amount of greater than about 0.01 wt. % based upon a totalweight of the second detailing agent, or in an amount of greater thanabout 0.1 wt. % based upon a total weight of the second detailing agent,or in an amount of greater than about 1 wt. % based upon a total weightof the second detailing agent, or in an amount of greater than about 2wt. % based upon a total weight of the second detailing agent, or in anamount of greater than about 3 wt. % based upon a total weight of thesecond detailing agent, or in an amount of greater than about 4 wt. %based upon a total weight of the second detailing agent, or in an amountof greater than about 5 wt. % based upon a total weight of the seconddetailing agent, or in an amount of greater than about 6 wt. % basedupon a total weight of the second detailing agent.

In some examples, the build material can be polyamide-12, polyetherblock, amide, or a combination thereof.

Build Material

The build material 106 may be a powder, a short fiber, a liquid, apaste, or a gel. In an example, the powder may be formed from, or mayinclude short fibers, that may, for example, have been cut into shortlengths from long strands, or threads of build material. The buildmaterial may be a polymeric material, metal material, or may be acomposite material of polymer and ceramic. Non-limiting examples ofbuild material include semi-crystalline thermoplastic materials with awide processing window of greater than 5° C. (i.e., the temperaturerange between the melting point and the re-crystallization temperature.Some specific examples of the polymeric build material 12 includepolyamides (PAs) (e.g., PA 11/nylon 11, PA 12/nylon 12, PA 6/nylon 6, PA8/nylon 8, PA 9/nylon 9, PA 66/nylon 66, PA 612/nylon 612, PA 812/nylon812, PA 912/nylon 912, etc.). Other specific examples of the buildmaterial include polyethylene, polyether, polyethylene terephthalate(PET), and an amorphous variation of these materials. Still otherexamples of suitable build material include polystyrene, polyacetals,polypropylene, polycarbonate, polyester, thermoplastic polyurethanes,other engineering plastics, and blends of any two or more of thepolymers listed herein. In an example, the build material may beselected from the group consisting of polyethylenes, polyethyleneterephthalates, polystyrenes, polyacetals, polypropylenes,polycarbonates, polyesters, thermoplastic polyurethanes, andcombinations thereof.

Any of the previously listed build materials may be combined withceramic particles to form the composite build material. Examples ofsuitable ceramic particles include metal oxides, inorganic glasses,carbides, nitrides, and borides. Some specific examples include alumina(Al₂O₃), glass, silicon mononitride (SIN), silicon dioxide (SiO₂),zirconia (ZrO₂), titanium dioxide (TiO₂), Na₂O/CaO/SiO₂ glass (soda-limeglass), silicon carbide (SiC), silicon nitride (Si3N4), yttriumoxide-stabilized zirconia (YTZ), or combinations thereof. The amount ofceramic particles that may be combined with the build material maydepend on the build material used, the ceramic particles used, and the3D part 40 to be formed.

The build material may have a melting point ranging from about 50° C. toabout 400° C. As an example, the build material may be a polyamidehaving a melting point of 180° C., or thermoplastic polyurethanes havinga melting point ranging from about 100° C. to about 165° C.

The build material may also include a binder, such as a polymer binder,a metal nanoparticle binder, or combinations thereof. The polymer bindermay be a semi-crystalline polymer, such as polypropylene andpolyethylene. The polymer binder may be a non-crystalline polymer, suchas polyethylene oxide, polyethylene glycol (solid), acrylonitrilebutadiene styrene, polystyrene, styrene-acrylonitrile resin, andpolyphenyl ether. The polymer binder may be one of polypropylene,polyethylene, poly(methyl methacrylate), low density polyethylene, highdensity polyethylene, polyethylene oxide, polyethylene glycol,acrylonitrile butadiene styrene, polystyrene, styrene-acrylonitrileresin, polyphenyl ether, polyamide 11, polyamide 12, polymethyl pentene,polyoxymethylene, polyethylene terephthalate, polybutyleneterephthalate, polyvinylidene fluoride, polytetrafluoroethylene,perfluoroalkoxy alkane, polyphenylene sulfide, polyurethanes, polyvinylalcohol, polylactic acid, or polyether ether ketone.

The polymer binder may have a melting point temperature less than about250° C., for example the melting point temperature may range from about50° C. to about 249° C., for example from about 60° C. to about 240° C.,and as a further example from about 70° C. to about 235° C.

Charging Agent

It is to be understood that the build material may also include acharging agent, a flow aid, or combinations thereof. A charging agentmay be added to suppress tribo-charging. Examples of suitable chargingagent(s) include, but are not limited to, aliphatic amines (which may beethoxylated), aliphatic amides, quaternary ammonium salts (e.g.,behentrimonium chloride or cocamidopropyl betaine), esters of phosphoricacid, polyethylene glycol esters, or polyols. Some suitable commerciallyavailable charging agents include a natural based ethoxylatedalkylamine, a fatty acid ester, and an alkane sulfonate.

In an example, the charging agent may be added in an amount ranging fromgreater than about 0 wt. % to less than about 5 wt. % based upon thetotal wt. % of the build material.

Flow Aid

A flow aid may be added to improve the flowability of the build materialby reducing the friction, the lateral drag, and the tribocharge buildup(by increasing the particle conductivity). Non-limiting examples ofsuitable flow aids include tricalcium phosphate, powdered cellulose,magnesium stearate, sodium bicarbonate, sodium ferrocyanide, potassiumferrocyanide, calcium ferrocyanide, bone phosphate, sodium silicate,silicon dioxide, calcium silicate, magnesium silicate, talcum powder,sodium aluminosilicate, potassium aluminum silicate, calciumaluminosilicate, bentonite, aluminum silicate, stearic acid, andpolydimethylsiloxane.

In an example, the flow aid may be added in an amount ranging fromgreater than about 0 wt. % to less than about 5 wt. % based upon thetotal wt. % of the build material.

Fusing Agents & Detailing Agents

The agent, such as a fusing agent or detailing agent, may be acomposition including various components that may be selectively appliedto the layer of the build material 106. Non-limiting examples ofcomponents of the agent include an aqueous vehicle, a non-aqueousvehicle, chemical binders, a colorant, a solvent, a co-solvent, asurfactant, a dispersant, a biocide, an anti-kogation agent, viscositymodifiers, buffers, stabilizers, and combinations thereof. The presenceof a co-solvent, a surfactant, and/or a dispersant in the agent mayassist in obtaining a particular wetting behavior with the buildmaterial 106. A fusing agent may include similar or different componentsthan the detailing agent. Additionally, a first detailing agent used toform an inner shell 20 may be the same or different from a seconddetailing agent used to form an external shell 30. Further, a firstfusing agent used to form a core 10 may be the same or different fromthe first detailing agent used to form an inner shell 20. In an example,more than one agent, such as a fusing agent and/or detailing agent(s),may be used during the 3D printing process.

In some examples, the agent may be one or more fusing agents. The fusingagent may be applied over the build material. Upon application ofenergy, such as electromagnetic radiation, the fusing agent absorbs theelectromagnetic radiation energy and allows successive layers of buildmaterial to fuse together to form a core of a 3D part.

In some examples, the agent may be a detailing agent. The detailingagent may provide a cooling effect. The detailing agent may beselectively applied to areas to achieve uniform temperatures.Additionally, the detailing agent may be selectively applied to areas inan effort to simplify cleaning and post-processing. In an example, thedetailing agent may be used in combination with an antistatic agent. Forexample, the detailing agent and the antistatic agent may be appliedsimultaneously to the same selected area from different printheads orthe detailing agent and the antistatic agent may be present in a singlecomposition and applied to the same selected area from the sameprinthead.

In some examples, an agent may include from about 1 wt. % to about 10wt. % of colorant, from about 10 wt. % to about 30 wt. % ofco-solvent(s), from about 0.5 wt. % to about 2 wt. % of dispersant(s),from 0.01 wt. % to about 1 wt. % of anti-kogation agent(s), from about0.1 wt. % to about 5 wt. % of binder(s), from about 0.05 wt. % to about0.1 wt. % biocide(s), and a balance of water. Another example mayinclude from about 1 wt. % to about 7 wt. % of colorant, from about 10wt % to about 30 wt. % of co-solvent(s), from about 0.25 wt. % to about2 wt. % of dispersant(s), from 0.05 wt. % to about 0.1 wt. % ofchelating agent(s), from about 0.005 wt. % to about 0.2 wt. % ofbuffer(s), from about 0.05 wt. % to about 0.1 wt. % biocide(s), and abalance of water.

A method of making a detailing agent may include combining variouscomponents to form the antistatic agent. In particular, the method mayinclude combining a co-solvent in an amount of from about 10 wt. % toabout 30 wt. %, a wetting additive, a surfactant in an amount of fromabout 0.1 wt % to about 3 wt %, a biocide in an amount of from about0.05 wt. % to about 0.1 wt. %, a salt of an alkali or alkaline earthmetal in an amount of from about 0.01 wt. % to about 20 wt. %, and abalance of water.

Following selective deposition of the agent onto selected areas of thelayer of the build material 106, the build area platform 102 may belowered as denoted by the arrow 112, e.g., along the z-axis. Inaddition, the spreader 108 may be moved across the build area platform102 to form a new layer of build material 106 on top of the previouslyformed layer. In an example, the spreader 108 may spread a layer ofbuild material 106. Moreover, the printhead 130 may deposit the agentonto predetermined areas of the new layer of build material 106. Forexample, the printhead 130 may deposit an antistatic agent over a firstselect area to form an external shell 30 of the 3D printed part 40. Asecond printhead may deposit a first and/or second fusing agent over asecond select area of a layer of the build material 106 to form an innershell 20. The first printhead may simultaneously or sequentially depositan antistatic agent to the second select area to form the inner shell20. In a further example, the second printhead may deposit a firstand/or second fusing agent over a third select area of a layer of thebuild material 106 to form a core 10. The above-described process may berepeated until a predetermined number of layers has been formed tofabricate a desired 3D part.

As also shown in FIG. 1, the 3D printer 100 may include a controller 140that may control operations of the build area platform 102, the buildmaterial supply 104, the spreader 108, the energy source 120, and theprinthead 130. The controller 140 is also depicted as being incommunication with a data store 150. The data store 150 may include datapertaining to a 3D part to be printed by the 3D printer 100.

A 3D printed part may be created from areas of the build material 106that have received the agent from the printhead 130. Upon application ofenergy 122, such as by heat lamps, ultraviolet lights, and the like, theselectively deposited agent may absorb the energy.

The applied energy 122 may be removed and 3D printed part may cool byremoval of the energy. Upon cooling, the formed 3D printed part maysolidify. The 3D printed part may include the external shell, the innershell, and the core, in which the core is at least partially encompassedby the inner shell. In an example, the core is at least about 50%encompassed by the inner shell, for example, at least about 75%, and asa further example, at least about 90% encompassed by the inner shell. Inan example, the core is completely encompassed by the shell. In anexample, the inner shell is at least about 50% encompassed by theexternal shell, for example, at least about 75%, and as a furtherexample, at least about 90% encompassed by the external shell. In anexample, the inner shell is completely encompassed by the externalshell.

Various manners in which an example 3D part may be fabricated arediscussed in greater detail with respect to the example methods 200 and300 respectively depicted in FIGS. 3 and 4. It should be apparent tothose of ordinary skill in the art that the methods 200 and 300 mayrepresent generalized illustrations and that other operations may beadded or existing operations may be removed, modified, or rearrangedwithout departing from the scopes of the methods 200 and 300.

The descriptions of the methods 200 and 300 are made with reference tothe 3D printer 100 illustrated in FIG. 1 for purposes of illustration.It should, however, be clearly understood that 3D printers and othertypes of apparatuses having other configurations may be implemented toperform either or both of the methods 200 and 300 without departing fromthe scopes of the methods 200 and 300.

Prior to execution of the method 200 or as part of the method 200, the3D printer 100 may access data pertaining to a 3D part that is to beprinted. By way of example, the controller 140 may access data stored inthe data store 150 pertaining to a 3D part that is to be printed. Thecontroller 140 may determine the number of layers of build material 106that are to be formed and the locations at which an agent from theprinthead 130 is to be selectively deposited on areas, to impartimproved strength, of each of the respective layers of build material106.

In some examples, fusing agent(s) may be compatible with polymers, suchas the build material 106. The fusing agent comprising at least oneantistatic agent may be able to reduce static charge that may accumulateon a 3D printed part 40. The fusing agent may be thermally stable at apolymer melt processing temperature.

For example, the antistatic agent may be thermally stable attemperatures for formation of the 3D printed part 40, for example, fromabout 50° C. to about 400° C. The antistatic agent may be liquid at roomtemperature, for example, about 25° C.

In an example, the antistatic agent does not absorb, or minimallyabsorbs, light in a near infrared wavelength (120 THz-400 THz/2500nm-750 nm). For example, 20% or less radiation may be absorbed in thenear infrared wavelength by the antistatic agent. Additionally, theantistatic agent may be transparent in the near infrared wavelength, forexample, 80% or greater radiation may be transmitted by the antistaticagent in a near infrared wavelength.

The fusing agent may be a composition that may include variouscomponents that may impart antistatic or charge dissipating properties.In an example, the fusing agent may include a water soluble antistaticagent compound. The fusing agent may be formed of conductive materialsthat are electrically conductive, thermally conductive, or both.

In some examples, disclosed herein is a fusing agent composition forthree-dimensional printing comprising: at least one antistatic agent inan amount of from about 0.01 wt % to about 20 wt % based on a totalweight of the fusing agent composition, at least one near infraredabsorbing compound, at least one surfactant, at least one organicsolvent, and water.

The antistatic agent is selected from the group consisting of Li₂NiBr₄,Li₂CuCl₄, LiCuO, LiCu₄O(PO₄)₂, LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃,C₆H₅COOLi, LiBr, Li₂CO₃, LiCl, C₆H₁₁ (CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄,Li₂SO₄, Li₂B₄O₇, LiAlCl₄, AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂,LiAg₂CrO₄, LiAg₂V₄O₁₁, LiSVO, LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄,LiCuS, LiPbCuS, LiFeS, LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂,LiCuCl₂, Li/Al—V₂O₅, lithium bis(oxalato)borate, LiN(SO₂CF₃)₂,LiN(SOCF₂CF₃)₂, LiAsF₆, LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃),LiN(SO₂F)(SO₂C₄F₉), LiOSO₂CF₃, and combinations thereof.

The antistatic agent includes a salt of an alkali or alkaline earthmetal selected from the group consisting of quaternary amines,chlorates, phosphates, carbonates, borates, phosphonates, sulfates,acetates, citrates, perchlorates, and combinations thereof.

The antistatic agent is thermally stable at a polymer melt processingtemperature.

The near infrared absorbing compound is selected from the groupconsisting of carbon black, oxonol, squarylium,chalcogenopyrylarylidene, bis(chalcogenopyrylo)polymethine,bis(aminoaryl)polymethine, merocyanine, trinuclear cyanine,indene-crosslinked polymethine, oxyindolidine, iron complexes, quinoids,nickel-dithiolene complex, cyanine dyes, and combinations thereof.

The cyanine dyes are selected from the group consisting of carbocyanine,azacarbocyanine, hemicyanine, styryl, diazacarbocyanine,triazacarbocyanine, diazahemicyanine, polymethinecyanine,azapolymethinecyanine, holopolar, indocyanine, diazahemicyanine dyes,and combinations thereof.

The near infrared absorbing compound is present in an amount of fromabout 0.1 wt % to about 10 wt % based on the total weight of the fusingagent.

In some examples, disclosed herein is a liquid functional agentcomposition for three-dimensional printing comprising: a first fusingagent comprising: at least one first antistatic agent, at least onefirst near infrared absorbing compound, at least one surfactant, atleast one organic solvent, and water; a second fusing agent comprisingat least one second near infrared absorbing compound; a first detailingagent; and a second detailing agent free of any near infrared absorbingcompound.

In some examples, the first detailing agent comprises at least onesecond antistatic agent; and the second detailing agent furthercomprises at least one third antistatic agent.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent are all the same; and the firstnear infrared absorbing compound and the second near infrared absorbingcompound are the same.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent are different; and the first nearinfrared absorbing compound and the second near infrared absorbingcompound are different.

In some examples, disclosed herein is a method of applying a liquidfunctional agent in three-dimensional printing comprising: (A) (i)depositing a layer of build material, (ii) selectively applying a firstfusing agent on the build material, and (iii) repeating (i) and (ii) atleast once to form a core of a three-dimensional part; wherein the firstfusing agent comprises: at least one first antistatic agent, at leastone first near infrared absorbing compound, at least one surfactant, atleast one organic solvent, and water; (B) applying a second fusing agentand a first detailing agent on the core of the three-dimensional part toform an inner shell at least partially enclosing the core, herein thefirst detailing agent comprises at least one second antistatic agent;and (C) applying a second detailing agent on the inner shell, whereinthe second detailing agent is free of any near infrared absorbingcompound.

In some examples, (B) the second fusing agent further comprises at leastone second near infrared absorbing compound; and (C) the seconddetailing agent further comprises at least one third antistatic agent.

In some examples, the first near infrared absorbing compound and thesecond near infrared absorbing compound are the same and selected fromthe group consisting of carbon black, oxonol, squarylium,chalcogenopyrylarylidene, bis(chalcogenopyrylo)polymethine,bis(aminoaryl)polymethine, merocyanine, trinuclear cyanine,indene-crosslinked polymethine, oxyindolidine, iron complexes, quinoids,nickel-dithiolene complex, cyanine dyes, and combinations thereof.

Antistatic Agents

In some examples, the antistatic agent may include a salt of an alkalior alkaline earth metal. The salt of the alkali or alkaline earth metalmay include quaternary amines, chlorates, phosphates, carbonates,borates, phosphonates, sulfates, acetates, citrates, and perchlorates.Non-limiting examples of carbonates include sodium carbonates, potassiumcarbonates, lithium carbonates, barium carbonates, magnesium carbonates,calcium carbonates, ammonium carbonates, cobaltous carbonates, ferrouscarbonates, lead carbonates, manganese carbonates, and nickelcarbonates. Non-limiting examples of perchlorates include sodiumperchlorate, potassium perchlorate, lithium perchlorate, bariumperchlorate, magnesium perchlorate, calcium perchlorate, ammoniumperchlorate, cobaltous perchlorate, ferrous perchlorate, leadperchlorate, manganese perchlorate, and nickel perchlorate. Non-limitingexamples of chlorates include sodium chlorates, potassium chlorates,lithium chlorates, barium chlorates, magnesium chlorates, calciumchlorates, ammonium chlorates, cobaltous chlorates, ferrous chlorates,lead chlorates, manganese chlorates, and nickel chlorates. Non-limitingexamples of phosphates include sodium phosphates, potassium phosphates,lithium phosphates, barium phosphates, magnesium phosphates, calciumphosphates, ammonium phosphates, cobaltous phosphates, ferrousphosphates, lead phosphates, manganese phosphates, and nickelphosphates. The antistatic agent may also be a sulfonimide or asulfonamide.

The antistatic agent may be present in a composition in an amountranging from about 0.01 wt. % to about 20 wt. % based upon the totalweight percent of the composition. In an example, the antistatic agentmay be present in a composition in an amount ranging from about 0.1 wt.% to about 15 wt. %, for example, from about 2 wt. % to about 13 wt. %,for example, about 4 wt. % based upon the total weight percent of thecomposition.

In some examples, the first antistatic agent, the second antistaticagent, and third antistatic agent can be thermally stable at a polymermelt processing temperature.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent can be independently selected fromthe group consisting of Li₂NiBr₄, Li₂CuCl₄, LiCuO, LiCu₄O(PO₄)₂.LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₅H₅COOLi, LiBr, Li₂CO₃, LiCl,C₅H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄, Li₂SO₄, Li₂B₄O₇, LiAlCl₄,AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁, LiSVO,LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄, LiCuS, LiPbCuS, LiFeS,LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅,lithium bis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂, LiAsF₆,LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₉),LiOSO₂CF₃, and combinations thereof.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent can be independently selected fromthe group consisting of a salt of an alkali or alkaline earth metalselected from the group consisting of quaternary amines, chlorates,phosphates, carbonates, borates, phosphonates, sulfates, acetates,citrates, perchlorates, and combinations thereof.

In some examples, the first antistatic agent can be present in an amountof from about 0.1 wt. % to about 10 wt. % based upon a total weight ofthe first fusing agent, or in an amount of from about 0.5 wt. % to about9 wt. % based upon a total weight of the first fusing agent, or in anamount of from about 1 wt. % to about 8 wt. % based upon a total weightof the first fusing agent, or in an amount of from about 2 wt. % toabout 7 wt. % based upon a total weight of the first fusing agent, or inan amount of less than about 10 wt. % based upon a total weight of thefirst fusing agent, or in an amount of less than about 9 wt. % basedupon a total weight of the first fusing agent, or in an amount of lessthan about 8 wt. % based upon a total weight of the first fusing agent,or in an amount of less than about 7 wt. % based upon a total weight ofthe first fusing agent, or in an amount of less than about 6 wt. % basedupon a total weight of the first fusing agent, or in an amount of lessthan about 5 wt. % based upon a total weight of the first fusing agent,or in an amount of less than about 4 wt. % based upon a total weight ofthe first fusing agent, or in an amount of greater than about 0.1 wt. %based upon a total weight of the first fusing agent, or in an amount ofgreater than about 0.5 wt. % based upon a total weight of the firstfusing agent, or in an amount of greater than about 1 wt. % based upon atotal weight of the first fusing agent, or in an amount of greater thanabout 2 wt. % based upon a total weight of the first fusing agent, or inan amount of greater than about 3 wt. % based upon a total weight of thefirst fusing agent, or in an amount of greater than about 4 wt. % basedupon a total weight of the first fusing agent, or in an amount ofgreater than about 5 wt. % based upon a total weight of the first fusingagent, or in an amount of greater than about 6 wt. % based upon a totalweight of the first fusing agent, or in an amount of greater than about7 wt. % based upon a total weight of the first fusing agent, or in anamount of greater than about 8 wt. % based upon a total weight of thefirst fusing agent, or in an amount of greater than about 9 wt. % basedupon a total weight of the first fusing agent.

In some examples, the second antistatic agent is present in an amount offrom about 0.01 wt. % to about 7 wt. % based upon a total weight of thefirst detailing agent, or in an amount of from about 0.1 wt. % to about6 wt. % based upon a total weight of the first detailing agent, or in anamount of from about 1 wt. % to about 5 wt. % based upon a total weightof the first detailing agent, or in an amount of from about 2 wt. % toabout 4 wt. % based upon a total weight of the first detailing agent, orin an amount of less than about 7 wt. % based upon a total weight of thefirst detailing agent, or in an amount of less than about 6 wt. % basedupon a total weight of the first detailing agent, or in an amount ofless than about 5 wt. % based upon a total weight of the first detailingagent, or in an amount of less than about 4 wt. % based upon a totalweight of the first detailing agent, or in an amount of less than about3 wt. % based upon a total weight of the first detailing agent, or in anamount of less than about 2 wt. % based upon a total weight of the firstdetailing agent, or in an amount of less than about 1 wt. % based upon atotal weight of the first detailing agent, or in an amount of greaterthan about 0.01 wt. % based upon a total weight of the first detailingagent, or in an amount of greater than about 0.1 wt. % based upon atotal weight of the first detailing agent, or in an amount of greaterthan about 1 wt. % based upon a total weight of the first detailingagent, or in an amount of greater than about 2 wt. % based upon a totalweight of the first detailing agent, or in an amount of greater thanabout 3 wt. % based upon a total weight of the first detailing agent, orin an amount of greater than about 4 wt. % based upon a total weight ofthe first detailing agent, or in an amount of greater than about 5 wt. %based upon a total weight of the first detailing agent, or in an amountof greater than about 6 wt. % based upon a total weight of the firstdetailing agent.

In some examples, the third antistatic agent is present in an amount offrom about 0.01 wt. % to about 7 wt. % based upon a total weight of thesecond detailing agent, or in an amount of from about 0.1 wt % to about6 wt. % based upon a total weight of the second detailing agent, or inan amount of from about 1 wt. % to about 5 wt. % based upon a totalweight of the second detailing agent, or in an amount of from about 2wt. % to about 4 wt. % based upon a total weight of the second detailingagent, or in an amount of less than about 7 wt. % based upon a totalweight of the second detailing agent, or in an amount of less than about6 wt. % based upon a total weight of the second detailing agent, or inan amount of less than about 5 wt. % based upon a total weight of thesecond detailing agent, or in an amount of less than about 4 wt. % basedupon a total weight of the second detailing agent, or in an amount ofless than about 3 wt. % based upon a total weight of the seconddetailing agent, or in an amount of less than about 2 wt. % based upon atotal weight of the second detailing agent, or in an amount of less thanabout 1 wt. % based upon a total weight of the second detailing agent,or in an amount of greater than about 0.01 wt. % based upon a totalweight of the second detailing agent, or in an amount of greater thanabout 0.1 wt. % based upon a total weight of the second detailing agent,or in an amount of greater than about 1 wt. % based upon a total weightof the second detailing agent, or in an amount of greater than about 2wt. % based upon a total weight of the second detailing agent, or in anamount of greater than about 3 wt. % based upon a total weight of thesecond detailing agent, or in an amount of greater than about 4 wt. %based upon a total weight of the second detailing agent, or in an amountof greater than about 5 wt. % based upon a total weight of the seconddetailing agent, or in an amount of greater than about 6 wt. % basedupon a total weight of the second detailing agent.

Binders

In some examples, the three-dimensional printing compositions and/orfusing/detailing agents, described herein, may further include othersuitable binders, for example, chemical binders, such as metal salts,sugars, sugar alcohols, polymeric or oligomeric sugars, low or moderatemolecular weight polycarboxylic acids, polysulfonic acids, water solublepolymers containing carboxylic or sulfonic moieties, and polyetheralkoxy silane. Some specific examples include glucose (C6H12O6), sucrose(C12H22O11), fructose (C6H12O6), maltodextrines with a chain lengthranging from 2 units to 20 units, sorbitol (C6H14O6), erythritol(C4H10O4), mannitol (C6H14O6), or a short chain polyacrylic acid.

Other suitable binders that may be used include water-dispersible orwater soluble polymers. Examples of polymer classes include acrylics,styrenics, polyethylenes, polypropylenes, polyesters, polyamides,polyurethanes, polyureas, polyethers, polycarbonates, polyacidanhydrides, and copolymers and/or combinations thereof. Such polymerparticles may be ionomeric, film-forming, non-film-forming, fusible, orheavily crosslinked, and may have a wide range of molecular weights andglass transition temperatures.

In some examples, the three-dimensional printing compositions and/orfusing/detailing agents, described herein, can include at least onebinder. In some examples, this binder can be a part of the polymericdispersion described above and/or added to the solvent system directly.

In some examples, the binder can comprise a polyurethane polymer, whichcan improve the durability of the ink composition. In some examples, thepolyurethane polymer can act as a binder to help bind the pigmentparticles together.

In some examples, the polyurethane can be a reaction product of apolyisocyanate having at least two isocyanate (—NCO) functionalities permolecule with, at least, one isocyanate-reactive group, such as apolyol, having at least two hydroxy groups or an amine. Suitablepolyisocyanates can include diisocyanate monomers and oligomers.

In some examples, the polyurethane can be a vinyl-urethane hybridpolymer or an acrylic-urethane hybrid polymer. In still other examples,the polyurethane can be an aliphatic polyurethane-acrylic hybridpolymer.

In some examples, the polyurethane can include a modified or unmodifiedpolymeric core of either polyurethane or a copolymer that includespolyurethane. Suitable polyurethanes can include aliphatic as well asaromatic polyurethanes.

In another example, the polyurethane can include an aromatic polyetherpolyurethane, an aliphatic polyether polyurethane, an aromatic polyesterpolyurethane, an aliphatic polyester polyurethane, an aromaticpolycaprolactam polyurethane, an aliphatic polycaprolactam polyurethane,or a combination thereof. In a more specific example, the polyurethanecan include an aromatic polyether polyurethane, an aliphatic polyetherpolyurethane, an aromatic polyester polyurethane, an aliphatic polyesterpolyurethane, and a combination thereof.

In some examples, the three-dimensional printing compositions and/orfusing/detailing agents, described herein, may include the binder in anamount of from about 0.5 wt % to about 20 wt % based on the total weightof the compositions and/or agents, or from about 1 wt % to about 10 wt%, or from about 2 wt % to about 8 wt %, or from about 3 wt % to about 7wt %.

Colorants

The colorant may be, for example, a pigment and/or dye. The colorant mayhave any color (e.g., cyan, magenta, yellow, white, etc.). Some examplesof a colorant include a set of cyan, magenta, and yellow, such as C1893A(cyan), C1984A (magenta), and C1985A (yellow); or C4801A (cyan), C4802A(magenta), and C4803A (yellow); all of which are available fromHewlett-Packard Company. Other commercially available colorants includeC9384A (printhead HP 72), C9383A (printhead HP 72), C4901A (printhead HP940), and C4900A (printhead HP 940).

Some examples of a white colorant include pigments, such as titaniumdioxide (TiO2), zinc oxide (ZnO), calcium carbonate (CaCO3), bariumsulfate (BaSO4), or combinations thereof. The colorant may, in someinstances, be dispersed with a dispersing additive. As such, thedispersing additive helps to uniformly distribute the colorantthroughout the agent. The dispersing additive may be present in theagent in an amount ranging from about 0.01 wt. % to about 1 wt. % basedon the total wt. % of the colorant. Some examples of the dispersingadditive include a water soluble acrylic acid polymer, a high molecularweight block copolymer with pigment affinic groups, and combinationsthereof.

In some examples, the three-dimensional printing compositions, fusingagents, and/or detailing agents, described herein, may further include acolorant. The colorant can be present in the composition/agent canimpart color to the resulting 3D part.

The colorant may be a pigment and/or dye having any suitable color.Examples of the colors include cyan, magenta, yellow, or combinationsthereof.

Examples of colorants include dyes, such as Acid Yellow 23 (AY 23), AcidYellow 17 (AY 17), Acid Red 52 (AR 52), Acid Red 289 (AR 289), ReactiveRed 180 (RR 180), Direct Blue 199 (DB 199), or pigments, such as PigmentBlue 15:3 (PB 15:3), Pigment Red 122 (PR 122), Pigment Yellow 155 (PY155), and Pigment Yellow 74 (PY 74).

Any standard color pigments may be used, such as phthalocyanines forblue, quinacridone for magenta or red, pigment yellow for yellow, white,black, or combinations thereof. Some commercially available examples ofthe white colorant are available from DuPont under the tradenameTI-PURE®, an example of which includes TI-PURE® R-706.

In some examples, dyes can be used. Examples include acid dyes (e.g.,Acid Red 52, Acid Red 289, Acid Yellow 23, Acid Yellow 17, orcombinations thereof), reactive dyes (e.g., Reactive Red 180, ReactiveBlack 31, or combinations thereof), and phthalocyanine dyes (e.g.,Direct Blue 199 and Pro-Jet Cyan dyes available from Fujifilm IndustrialColorants).

Some examples of the colorant(s) can include a set of cyan, magenta, andyellow inks, such as C1893A (cyan), C1984A (magenta), and C1985A(yellow); or C4801A (cyan), C4802A (magenta), and C4803A (yellow); allof which are available from Hewlett-Packard Company.

In some examples, a colored ink can include a colorant (as describedabove), a solvent, a surfactant, and water. In some examples, coloredink can include further additives.

In some examples, the colored ink(s) can include a pigment, whichimparts color to the build material upon application. The pigment may bea self-dispersing pigment or the soft polymer precursor may act as asuitable dispersant for dispersing the pigment throughout thecomposition. In some examples, the colored ink(s) can include a colorant(e.g., pigment and/or dye) having a color including white or black.Examples of colors include cyan, magenta, yellow, white, black, ormixtures thereof.

The amount of the colorant that may be present in the three-dimensionalprinting compositions and/or agents ranges from about 0.1 wt % to about20 wt % based on the total weight of the compositions and/or agents. Insome examples, the amount of the colorant that may be present in thecompositions and/or agents ranges from about 1 wt % to about 15 wt %based on the total weight of the compositions and/or agents. In someexamples, the amount of the colorant that may be present in thecompositions and/or agents ranges from about 1 wt % to about 10 wt %based on the total weight of the compositions and/or agents.

Surfactants

Surfactant(s) may be used to improve the wetting properties and thejettability of the agent. Examples of suitable surfactants may include aself-emulsifiable, nonionic wetting agent based on acetylenic diolchemistry, a nonionic fluorosurfactant, and combinations thereof. Inother examples, the surfactant may be an ethoxylated low-foam wettingagent or an ethoxylated wetting agent and molecular defoamer. Stillother suitable surfactants include non-ionic wetting agents andmolecular defoamers or water-soluble, non-ionic surfactants. In someexamples, it may be desirable to utilize a surfactant having ahydrophilic-lipophilic balance (HLB) less than 10. Whether a singlesurfactant is used or a combination of surfactants is used, the totalamount of surfactant(s) in the agent may range from about 0.1 wt % toabout 3 wt % based on the total wt % of the agent.

In some examples, the other surfactants can include wetting agent(s)and/or surface tension reducing agent(s).

Examples of suitable wetting agents can include non-ionic surfactants.Some specific examples include a self-emulsifiable, non-ionic wettingagent based on acetylenic diol chemistry (e.g., SURFYNOL® SEF from AirProducts and Chemicals, Inc.), a non-ionic fluorosurfactant (e.g.,CAPSTONE® fluorosurfactants from DuPont, previously referred as ZONYLFSO), and combinations thereof. In other examples, the wetting agent isan ethoxylated low-foam wetting agent (e.g., SURFYNOL® 440 or SURFYNOL®CT-111 from Air Products and Chemical Inc.) or an ethoxylated wettingagent and molecular defoamer (e.g., SURFYNOL® 420 from Air Products andChemical Inc.). Still other suitable wetting agents include non-ionicwetting agents and molecular defoamers (e.g., SURFYNOL® 104E from AirProducts and Chemical Inc.) or water-soluble, non-ionic surfactants(e.g., TERGITOL™ TMN-6, TERGITOL™ 15S7, and TERGITOL™ 15S9 from The DowChemical Company). In some examples, an anionic surfactant may be usedin combination with the non-ionic surfactant. In some examples, it maybe appropriate to utilize a wetting agent having ahydrophilic-lipophilic balance (HLB) less than 10.

In some examples, wetting agent(s) may be present in the fusing agent(s)and/or detailing agent(s) in an amount ranging from about 0.1 wt % toabout 4 wt % of the total weight of the compositions/agents. In anexample, the amount of the wetting agent(s) present in thecompositions/agents is about 0.1 wt % based on the total weight of thecompositions/agents. In another example, the amount of the wettingagent(s) present in the compositions/agents is about 0.04 wt % based onthe total weight of the compositions/agents.

The fusing agent(s) and/or detailing agent(s) may also include surfacetension reduction agent(s). Any of the previously mentioned wettingagents/surfactants may be used to reduce the surface tension. As anexample, the surface tension reduction agent may be theself-emulsifiable, non-ionic wetting agent based on acetylenic diolchemistry (e.g., SURFYNOLO® SEF from Air Products and Chemicals, Inc.).

The surface tension reduction agent(s) may be present in thecompositions/agents in an amount ranging from about 0.1 wt % to about 4wt % of the total weight of the compositions/agents. In an example, theamount of the surface tension reduction agent(s) present in thecompositions/agents is about 1.5 wt % based on the total weight of thecompositions/agents. In another example, the amount of the surfacetension reduction agent(s) present in the compositions/agents is about0.6 wt % compositions/agents.

When a surfactant is both a wetting agent and a surface tensionreduction agent, any of the ranges presented herein for the wettingagent and the surface tension reduction agent may be used for thesurfactant.

Co-Solvents

Some examples of a co-solvent include1-(2-hydroxyethyl)-2-pyrollidinone, 2-Pyrrolidinone, 1,5-Pentanediol,Triethylene glycol, Tetraethylene glycol, 2-methyl-1,3-propanediol,dipropylene glycol methyl ether, tripropylene glycol butyl ether,dipropylene glycol butyl ether, triethylene glycol butyl ether,1,6-Hexanediol, Tripropylene glycol methyl ether, N-methylpyrrolidone,Ethoxylated Glycerol-1 (LEG-1), 1,2-hexanediol, and combinationsthereof.

The co-solvent may be present in an amount ranging from about 10 wt. %to about 30 wt. % based on the total wt. % of the agent.

In some examples, the co-solvent can include 1-methyl-2-pyrrolidone(1M2P), 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone,dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and combinationsthereof.

Biocides

Examples of suitable biocides include an aqueous solution of1,2-benzisothiazolin-3-one, quaternary ammonium compounds, and anaqueous solution of methylisothiazolone. Whether a single biocide isused or a combination of biocides is used, the total amount ofbiocide(s) in the fusing agent(s) and/or detailing agent(s) may rangefrom about 0.1 wt % to about 1 wt % with respect to the total wt % ofthe agent(s).

Anti-Kogation Agents

Non-limiting examples of suitable anti-kogation agents includeoleth-3-phosphate or polyoxyethylene (3) oleyl mono/di-phosphate, ametal chelator/chelating agent, such as methylglycinediacetic acid, andcombinations thereof.

Liquid Vehicle

The fusing agents and/or detailing agents disclosed herein can include aliquid vehicle. Liquid vehicle(s), as described herein, can includesolvent(s)/co-solvent(s) described hereinabove and solvent(s) other thanthe solvent(s)/co-solvents described hereinabove. The liquid vehicle(s),as described herein, can generally include solvent(s) in which a nearinfrared absorbing agent and/or antistatic agent can be added to formthe fusing agent and/or detailing agent.

Examples of liquid vehicles can include water, alone or in combinationwith a mixture of a variety of additional components. Examples of theseadditional components may include water soluble co-solvent(s), wettingagent(s), surface tension reduction agent(s), emulsifier(s), scaleinhibitor(s), anti-deceleration agent(s), chelating agent(s), and/orantimicrobial agent(s).

In some examples, the liquid vehicle can be present in the fusing agentand/or detailing agent in an amount of from about 1 wt % to about 95 wt% based on the total weight of the fusing agent and/or detailing agent(agent(s)). In some examples, the liquid vehicle can be present in theagent in an amount of from about 5 wt % to about 95 wt % based on thetotal weight of the agent. In some examples, the liquid vehicle can bepresent in the agent in an amount of from about 10 wt % to about 70 wt %based on the total weight of the agent. In some examples, the liquidvehicle can be present in the agent in an amount of from about 20 wt %to about 60 wt % based on the total weight of the agent. In someexamples, the liquid vehicle can be present in the agent in an amount offrom about 50 wt % to about 95 wt % based on the total weight of theagent. In some examples, the liquid vehicle can be present in the agentin an amount of from about 60 wt % to about 85 wt % based on the totalweight of the agent.

The co-solvent can be present in the liquid vehicle in an amount rangingfrom about 0.1 wt % to about 20 wt % based on the total weight of theliquid vehicle.

Some examples of co-solvents can include 2-pyrrolidinone,hydroxyethyl-2-pyrrolidone, diethylene glycol, 2-methyl-1,3-propanediol,tetraethylene glycol, tripropylene glycol methyl ether, dipropyleneglycol methyl ether, tripropylene glycol butyl ether, dipropylene glycolbutyl ether, triethylene glycol butyl ether, 1,2-hexanediol,2-hydroxyethyl pyrrolidinone, 2-hydroxyethyl-2-pyrrolidinone,1,6-hexanediol, and combinations thereof.

The aqueous nature of the agents can enable them to penetrate, at leastpartially, into the layer of the polymeric or polymeric composite buildmaterial particles. The build material particles may be hydrophobic, andthe presence of the wetting agent(s) in the compositions/agents mayassist in obtaining a particular wetting behavior.

In some examples, water can be present in the agent(s) in amountsgreater than about 30 wt % based on the total weight of the agent(s). Insome examples, the water can be present in the agent(s) in amounts fromabout 40 wt % to about 90 wt % based on the total weight of theagent(s). In other examples, the agent(s) can include from about 45 wt %to about 80 wt % water based on the total weight of the agent(s). Infurther examples, the agent(s) can include from about 50 wt % to about70 wt % water based on the total weight of the agent(s).

The liquid vehicle may also include water soluble organic solvent(s). Insome examples, the water soluble organic solvent(s) may be the same typeof solvent as the solvent(s)/co-solvent(s) described hereinabove. Inthese examples, the water soluble organic solvent(s) may be1-methyl-2-pyrrolidone (1M2P), 2-pyrrolidone,1-(2-hydroxyethyl)-2-pyrrolidone, dimethylformamide (DMF), dimethylsulfoxide (DMSO), or a combination thereof. In other examples, the watersoluble organic solvent(s) may be different than thesolvent(s)/co-solvent(s) described hereinabove. For example, twodifferent solvent(s)/co-solvent(s) may be selected. For another example,the water soluble organic solvent(s) may be 1,5-pentanediol, triethyleneglycol, tetraethylene glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol,tripropylene glycol methyl ether, or a combination thereof.

The water soluble organic solvent(s) may be present in the agent(s) inan amount ranging from about 2 wt % to about 80 wt % of the total weightof the agent(s). In an example, the amount of the water soluble organicsolvent(s) present in the agent(s) is greater than about 30 wt % basedon the total weight of the agent(s), or the amount of the water solubleorganic solvent(s) present in the agent(s) is greater than about 40 wt %based on the total weight of the agent(s), or the amount of the watersoluble organic solvent(s) present in the agent(s) is greater than about50 wt % based on the total weight of the agent(s), or the amount of thewater soluble organic solvent(s) present in the agent(s) is greater thanabout 60 wt % based on the total weight of the agent(s), or the amountof the water soluble organic solvent(s) present in the agent(s) isgreater than about 70 wt % based on the total weight of the agent(s), orthe amount of the water soluble organic solvent(s) present in theagent(s) is greater than about 80 wt % based on the total weight of theagent(s), or the amount of the water soluble organic solvent(s) presentin the agent(s) is greater than about 85 wt % based on the total weightof the agent(s), or the amount of the water soluble organic solvent(s)present in the agent(s) is greater than about 90 wt % based on the totalweight of the agent(s).

The liquid vehicle may also include emulsifier(s). Examples of suitableemulsifiers include oleth-3-phosphate (commercially available asCRODAFOS™ O3A or CRODAFOS™ N-3 acid) or dextran 500 k. Other suitableexamples of the emulsifiers include CRODAFOS™ HCE (phosphate-ester fromCroda Int.), CRODAFOS® N10 (oleth-10-phosphate from Croda Int.).

The emulsifier(s) may be present in the agent(s) in an amount rangingfrom about 0.1 wt % to about 5 wt % of the total weight of the agent(s).In an example, the amount of the emulsifier(s) present in the agent(s)is less than about 3 wt % based on the total weight of the agent(s). Inanother example, the amount of the emulsifier(s) present in the agent(s)is less than about 2 wt % based on the total weight of the agent(s).

The liquid vehicle may further include scale inhibitor(s) oranti-deceleration agent(s). One suitable scaleinhibitor/anti-deceleration agent is an alkyldiphenyloxide disulfonate(e.g., DOWFAX™ 8390 and DOWFAX™ 2A1 from The Dow Chemical Company).

The scale inhibitor(s)/anti-deceleration agent(s) may be present in theagent(s) in an amount ranging from about 0.05 wt % to about 5 wt % ofthe total weight of the agent(s). In an example, the scaleinhibitor(s)/anti-deceleration agent(s) is/are present in the agent(s)in an amount of about 0.25 wt % based on the total weight of theagent(s). In another example, the scale inhibitor(s)/anti-decelerationagent(s) is/are present in the agent(s) in an amount of about 0.1 wt %based on the total weight of the agent(s).

The liquid vehicle may also include chelating agent(s). The chelatingagent may be included to eliminate the deleterious effects of any heavymetal impurities. Examples of suitable chelating agents include disodiumethylenediaminetetraacetic acid (EDTA-Na), ethylene diamine tetra aceticacid (EDTA), and methylglycinediacetic acid (e.g., TRILON® M from BASFCorp.).

Whether a single chelating agent is used or a combination of chelatingagents is used, the total amount of chelating agent(s) in the agent(s)may range from 0 wt % to about 2 wt % based on the total weight of theagent(s). In an example, the chelating agent is present in the agent(s)in an amount of from about 0.01 wt % to about 1 wt % based on the totalweight of the agent(s).

The liquid vehicle may also include antimicrobial agent(s). Suitableantimicrobial agents include biocides and fungicides. Exampleantimicrobial agents may include the NUOSEPT® (Ashland Inc.), UCARCIDE™or KORDEK™ (Dow Chemical Co.), and PROXEL® (Arch Chemicals) series,ACTICIDE® M20 (Thor), and combinations thereof.

In an example, the liquid vehicle may include a total amount ofantimicrobial agents that ranges from about 0.05 wt % to about 0.5 wt %based on the total weight of the fusing and/or detailing agent.

Method(s) of Making Fusing/Detailing Agent(s)

Also disclosed herein is a method of making the fusing agent(s) and/orthe detailing agent(s). In some examples, the agents can be made by amethod comprising: mixing a near infrared absorbing agent and/orantistatic agent with solvent, water, and an additive selected from thegroup consisting of an emulsifier, a surface tension reduction agent, awetting agent, a scale inhibitor, an anti-deceleration agent, achelating agent, an antimicrobial agent, and a combination thereof.

The above mixing can include stirring, shaking, grinding, milling, andcombinations thereof to form a substantially homogeneous mixture of thecompositions/agents.

3D Printing Method(s)

The 3D printer 100 is depicted in FIG. 1 as including a build areaplatform 102, a build material supply 104 containing the build material106, and a spreader 108. The build area platform 102 may be integratedwith the 3D printer 100 or may be a component that is separatelyinsertable into the 3D printer 100, e.g., the build area platform 102may be a module that is available separately from the 3D printer 100.The build material supply 104 may be a container or surface that is toposition the build material 106 between the spreader 108 and the buildarea platform 102. The build material supply 104 may be a hopper or asurface upon which the build material 106 may be supplied. The spreader108 may be moved in a direction as denoted by the arrow 110, e.g., alongthe y-axis, over the build material supply 104 and across the build areaplatform 102 to spread a layer of the build material 106 over a surfaceof the build area platform 102.

In one example, a printhead may selectively apply a fusing agent over aselect area of a layer of the build material 106 to form a core 10 of a3D printed part 40. Then an inner shell 20 of a 3D printed part 40 canbe formed by selectively applying a second fusing agent and a firstdetailing agent at least over a portion of the core 10. The externalshell 30 can be formed over at least a portion of the inner shell 20 byselectively applying a second detailing agent on the inner shell 20. Thefirst fusing agent, the second fusing agent, the first detailing agent,and the second detailing agent can be applied using one or moreprintheads.

In some examples, the core 10 comprises an antistatic agent but theinner shell 20 and the external shell 30 are free of the antistaticagent. In some examples, the core comprises an antistatic agent and theinner shell 20 and the external shell 30 also include antistatic agents,which can be the same as or different from the antistatic agent in thecore 10. In some examples, the core 10 comprises an antistatic agent andonly one of either the inner shell 20 or the external shell 30 includesan antistatic agent, which can be the same as or different from theantistatic agent in the core 10.

In some examples, the core 10 further comprises a near infraredabsorbing compound but the inner shell 20 and the external shell 30 arefree of any near infrared absorbing compound. In some examples, the core10 further comprises a near infrared absorbing compound and the innershell 20 includes a near infrared absorbing compound but the externalshell 30 does not include any near infrared absorbing compound, whereinthe near infrared absorbing compounds in the core 10 and in the innershell 20 can be the same or different. In some examples, the core 10further comprises a near infrared absorbing compound and the inner shell20 and the external shell 30 include a near infrared absorbing compound,wherein the near infrared absorbing compounds in the core 10, the innershell 20, and the external shell 30, can be all the same or alldifferent or have two the same with one different.

In an example, the inner shell 20 may have a thickness ranging fromabout 0 mm to about 5 mm, for example, from about 0.2 mm to about 1.5mm, and as a further example, from about 0.5 mm to about 1 mm. In anexample, the external shell 30 may have a thickness ranging from about 0mm to about 5 mm, for example, from about 0.2 mm to about 1.5 mm, and asa further example, from about 0.5 mm to about 1 mm.

The 3D printer 100 is further depicted as including a printhead 130 thatmay be scanned across the build area platform 102 in the directionindicated by the arrow 132, e.g., along the y-axis. The printhead 130may be, for instance, a thermal inkjet printhead or a piezoelectricprinthead, and may extend a width of the build area platform 102.Although a single printhead 130 has been depicted in FIG. 1, it shouldbe understood that multiple printheads may be used that span the widthof the build area platform 102. Additionally, the printheads 130 may bepositioned in multiple printbars. The printhead 130 may also deposit anagent, such as a fusing agent, a detailing agent, and/or an antistaticagent, over a selected area of a layer of the build material 106. In anexample, multiple printheads 130 may independently deposit the same ordifferent agent over a selected area of a layer of the build material106. In an example, the multiple printheads 130 may simultaneously orsequentially deposit the same or different agents over a selected areaof a layer of the build material 106.

In some examples, layer(s) of the build material comprising at least onepolymer (see various options described hereinabove) can be applied ordeposited in a fabrication bed of a 3D printer. The applied layer(s) canbe exposed to heating, which can be performed to pre-heat the buildmaterial. Thus, the heating temperature may be below the melting pointof the build material. As such, the temperature selected can depend uponthe build material that is used. As examples, the heating temperaturemay be from about 5° C. to about 50° C. below the melting point of thebuild material. In an example, the heating temperature can range fromabout 50° C. to about 400° C. In another example, the heatingtemperature can range from about 150° C. to about 170° C.

Pre-heating the layer(s) of the build material may be accomplished usingany suitable heat source that exposes all of the build material to theheat. Examples of the heat source can include a thermal heat source oran electromagnetic radiation source (e.g., infrared (IR), microwave, orcombination thereof).

After pre-heating the layer(s) of the build material, the fusingagent(s) can be selectively applied on at least a portion of the buildmaterial in the layer(s). The fusing agent(s) described herein can bedispensed from an inkjet printhead, such as a thermal inkjet printheador a piezoelectric inkjet printhead. The printhead can be adrop-on-demand printhead or a continuous drop printhead.

The printhead may include an array of nozzles through which drops of thecompositions/agents described herein can be ejected. In some examples,printhead can deliver variable size drops of the compositions/agents.

Before or after selectively applying the fusing agent(s) describedherein on the portion(s) of the build material, colored ink(s) can beapplied to portion(s) of the build material. After thecompositions/agents and in some instances the colored ink(s) areselectively applied in the specific portions of the layer(s) of thebuild material, the entire object(s) or part(s) is exposed to infraredradiation.

The infrared radiation can be emitted from a radiation source, such asan IR (e.g., near-IR) curing lamp, or IR (e.g., near-IR) light emittingdiodes (LED), or lasers with specific IR or near-IR wavelengths. Anyradiation source may be used that emits a wavelength in the infraredspectrum, for example near-infrared spectrum. The radiation source maybe attached, for example, to a carriage that also holds theprinthead(s). The carriage may move the radiation source into a positionthat is adjacent to the fabrication bed containing the 3D printedobject(s) or part(s). The radiation source may be programmed to receivecommands from a central processing unit and to expose the layer(s) ofthe build material including the compositions/agents to the infraredradiation.

The length of time the radiation is applied for, or energy exposuretime, may be dependent, for example, on characteristics of the radiationsource, characteristics of the build material, and/or characteristics ofthe compositions/agents.

The fusing agent(s) described herein can enhance the absorption of theradiation, convert the absorbed radiation to thermal energy, and promotethe transfer of the thermal heat to the build material in contacttherewith. In an example, the fusing agent(s) can sufficiently elevatethe temperature of the build material above the melting point(s),allowing curing (e.g., sintering, binding, or fusing) of the buildmaterial particles to take place.

In some examples, portions of the build material that do not have thefusing agent(s) applied thereto do not absorb enough energy to fuse.However, the generated thermal energy may propagate into the surroundingbuild material that does not have the fusing agent(s) applied thereto.The propagation of thermal energy may cause at least some of the buildmaterial sans fusing agent to partially fuse.

Exposure to radiation can complete the formation of the core of 3Dprinted object(s) or part(s).

The same or different printhead(s) can be used to form an inner shelland then an external shell by selectively applying detailing agents, asdiscussed above.

In some examples, the completed 3D printed object(s) or part(s) may beremoved from the fabrication bed and any uncured build material may beremoved from the 3D part(s) or object(s).

In some examples, the unfused build material may be washed and thenreused.

As shown in FIG. 3, a method of three-dimensional printing 300 cancomprise: (i) depositing a layer of build material 302; (ii) selectivelyapplying a first fusing agent on the build material 304, wherein thefirst fusing agent comprises at least one first antistatic agent; and(iii) repeating (i) and (ii) at least once 306 to form a core of athree-dimensional part 308.

The method can, in some examples, further comprise: (iv) applying asecond fusing agent and a first detailing agent on the core of thethree-dimensional part to form an inner shell at least partiallyenclosing the core, wherein the first detailing agent comprises at leastone second antistatic agent; and (v) applying a second detailing agenton the inner shell, wherein the second detailing agent is free of anynear infrared absorbing compound.

The second fusing agent further comprises at least one second nearinfrared absorbing compound; and the second detailing agent furthercomprises at least one third antistatic agent.

In some examples, the first antistatic agent, the second antistaticagent, and the third antistatic agent are different; and the first nearinfrared absorbing compound and the second near infrared absorbingcompound are different.

The first antistatic agent, the second antistatic agent, and the thirdantistatic agent are the same, and the first antistatic agent, thesecond antistatic agent, and the third antistatic agent areindependently selected from the group consisting of Li₂NiBr₄, Li₂CuCl₄,LiCuO, LiCu₄O(PO₄)₂, LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₆H₅COOLi,LiBr, Li₂CO₃, LiCl, C₆H₁₁(CH₂)₃CO₂Li, LiBO₂, Li₃PO₄, Li₂SO₄, Li₂B₄O₇,LiAlCl₄, AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁,LiSVO, LiCSVO, CF₃SO₃Li, LiCuS, LiPbCuS, LiFeS, LiBi₂Pb₂O₅, LiBi₂O₃,LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅, lithiumbis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂, LiAsF₆, LiC(SO₂CF₃)₃,LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₆), LiOSO₂CF₃, andcombinations thereof; the first antistatic agent, the second antistaticagent, and the third antistatic agent are independently selected fromthe group consisting of a salt of an alkali or alkaline earth metalselected from the group consisting of quaternary amines, chlorates,phosphates, carbonates, borates, phosphonates, sulfates, acetates,citrates, perchlorates, and combinations thereof.

The first antistatic agent is present in an amount of from about 0.1 wt.% to about 10 wt. % based upon a total weight of the first fusing agent;the second antistatic agent is present in an amount of from about 0.01wt. % to about 7 wt. % based upon a total weight of the first detailingagent; and the third antistatic agent is present in an amount of fromabout 0.01 wt. % to about 7 wt. % based upon a total weight of thesecond detailing agent.

The first fusing agent further comprises water, at least one organicsolvent, at least one surfactant, and at least one biocide.

As shown in FIG. 4, a method of three-dimensional printing 400 cancomprise: (i) depositing a layer of build material 402; (ii) selectivelyapplying a first fusing agent comprising: at least one antistatic agenton the build material, at least one first near infrared absorbingcompound, at least one surfactant, at least one organic solvent, andwater 404; (iii) repeating (i) and (ii) at least once to form a core ofa three-dimensional part 406; (iv) applying a second fusing agent and afirst detailing agent on the core of the three-dimensional part to forman inner shell at least partially enclosing the core 408, wherein thesecond fusing agent comprises at least one second near infraredabsorbing compound, and wherein the first detailing agent is free of anyantistatic agent; and (v) applying a second detailing agent on the innershell to at least partially enclose the inner shell and form an externalshell 410, wherein the second detailing agent is free of (a) any nearinfrared absorbing compound and (b) any antistatic agent.

Unless otherwise stated, any feature described hereinabove can becombined with any example or any other feature described herein.

In describing and claiming the examples disclosed herein, the singularforms “a,” “an,” and “the” include plural referents unless the contextclearly dictates otherwise.

It is to be understood that concentrations, amounts, and other numericaldata may be expressed or presented herein in range formats. It is to beunderstood that such range formats are used merely for convenience andbrevity and thus should be interpreted flexibly to include not just thenumerical values explicitly recited as the end points of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. As an illustration, a numerical range of “about 1wt % to about 5 wt %” should be interpreted to include not just theexplicitly recited values of about 1 wt % to about 5 wt %, but alsoinclude individual values and subranges within the indicated range.Thus, included in this numerical range are individual values such as 2,3.5, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc.This same applies to ranges reciting a single numerical value.

Reference throughout the specification to “one example,” “someexamples,” “another example,” “an example,” and so forth, means that aparticular element (e.g., feature, structure, and/or characteristic)described in connection with the example is included in at least oneexample described herein, and may or may not be present in otherexamples. In addition, it is to be understood that the describedelements for any example may be combined in any suitable manner in thevarious examples unless the context clearly dictates otherwise.

Unless otherwise stated, references herein to “wt %” of a component areto the weight of that component as a percentage of the whole compositioncomprising that component. For example, references herein to “wt %” of,for example, a solid material such as polyurethane(s) or colorant(s)dispersed in a liquid composition are to the weight percentage of thosesolids in the composition, and not to the amount of that solid as apercentage of the total non-volatile solids of the composition.

If a standard test is mentioned herein, unless otherwise stated, theversion of the test to be referred to is the most recent at the time offiling this patent application.

All amounts disclosed herein and in the examples below are in wt %unless indicated otherwise.

To further illustrate the present disclosure, examples are given herein.It is to be understood that these examples are provided for illustrativereasons and are not to be construed as limiting the scope of the presentdisclosure.

EXAMPLES Example 1

A fusing agent was prepared using the formulation shown in Table 1below:

TABLE 1 Wt. % Carbon Black (90 nm particle size) 5 Styrene AcrylicPolymeric Stabilizer 2.5 2-Pyrrolidinone 19 Triethylene glycol 8 TEGO ®Wet 510 0.75 CRODAFOS ® 03A 0.45 Trilon ® M (aqueous solution of thetrisodium 0.08 salt of methylglycinediacetic acid) Acticide ® B20 0.18Acticide ® M20 0.14 lithium bis-trifluoromethanesulfonimide 1.0 (HQ-115)Water Balance

The fusing agent including an antistatic agent (lithiumbis-trifluoromethanesulfonimide) and a near infrared absorbing compound(carbon black) was used in a three-dimensional printer using a polyetherblock amide. The fusing agent was printed throughout the entire volumeof the core only.

The resistivity of the printed part was measured with an ohmmeter (V=100volts, DC). Each three-dimensional printed part was squeezed between twoconductive electrodes and conductive rubber pads. Each part was measuredthree times, in different locations, and the values averaged.

Two sets of cubes (10 mm3) were printed with the polyether block amide.Within each set increasing amounts of the agent of the formulationdescribed above were used (ranging from 0.00% to 0.60% solids). As canbe seen from the data in FIG. 5, the increasing amounts of agent presentin the three-dimensional part decreased the bulk resistivity of thethree-dimensional part.

Example 2

A first fusing agent was prepared using the formulation shown in Table 2below:

TABLE 2 Wt. % Carbon Black (90 nm particle size) 5 Styrene AcrylicPolymeric Stabilizer 2.5 2-Pyrrolidinone 19 Triethylene glycol 8 TEGO ®Wet 510 0.75 CRODAFOS ® 03A 0.45 Trilon ® M (aqueous solution of thetrisodium 0.08 salt of methylglycinediacetic acid) Acticide ® B20 0.18Acticide ® M20 0.14 lithium bis-trifluoromethanesulfonimide 1.0 (HQ-115)Water Balance

A second fusing agent was prepared using the formulation shown in Table3 below:

TABLE 3 Wt. % Carbon Black (90 nm particle size) 5 Styrene AcrylicPolymeric Stabilizer 2.5 2-Pyrrolidinone 19 Triethylene glycol 8 TEGO ®Wet 510 0.75 CRODAFOS ® 03A 0.45 Trilon ® M (aqueous solution of thetrisodium 0.08 salt of methylglycinediacetic acid) Acticide ® B20 0.18Acticide ® M20 0.14 lithium bis-trifluoromethanesulfonimide 1.0 (HQ-115)Water Balance

A detailing agent was prepared using the formulation shown in Table 4below:

TABLE 4 Wt. % 2-Pyrrolidinone 19 Triethylene glycol 8 TEGO ® Wet 5100.75 CRODAFOS ® 03A 0.45 Trilon ® M (aqueous solution of the trisodium0.08 salt of methylglycinediacetic acid) Acticide ® B20 0.18 Acticide ®M20 0.14 lithium bis-trifluoromethanesulfonimide 4.0 (HQ-115) WaterBalance

The first fusing agent including an antistatic agent (lithiumbis-trifluoromethanesulfonimide) and a near infrared absorbing compound(carbon black) was used in a three-dimensional printer using a polyetherblock amide. The first fusing agent was printed throughout the entirevolume of the core. Then the second fusing agent and the detailing agentwere applied over the core to form an inner shell (about 125 micronsthick) and then the second detailing agent was applied over the innershell to form an external shell (about 125 microns thick).

The resistivity of the printed part was measured with an ohmmeter (V=100volts, DC). Each three-dimensional printed part was squeezed between twoconductive electrodes and conductive rubber pads. Each part was measuredthree times, in different locations, and the values averaged.

One set of cubes (10 mm3) were printed with the polyether block amide.Within each set increasing amounts of the agent of the formulationdescribed above were used (ranging from 0.00% to 0.60% solids). As canbe seen from the data in FIGS. 6 and 7, the increasing amounts of agentpresent in the three-dimensional part decreased the surface and bulkresistivity of the three-dimensional part.

A decrease in surface and/or bulk resistivity indicates that thepresence of the antistatic agent in the core of the three-dimensionalprinted part is dissipating static charge. The three-dimensional printedpart is less likely to build-up static charge on its surface and is lesslikely to have an ESD event. Because the antistatic agent is locatedwithin the core of the three-dimensional printed part it is not able tocrack or rub off like post-process coatings and may provide a permanentprotection against a static charge.

Although described specifically throughout the entirety of the instantdisclosure, representative examples of the present disclosure haveutility over a wide range of applications, and the above discussion isnot intended and should not be construed to be limiting, but is offeredas an illustrative discussion of examples of the disclosure.

What is claimed is:
 1. A method of three-dimensional printingcomprising: (i) depositing a layer of build material; (ii) selectivelyapplying a first fusing agent on the build material, wherein the firstfusing agent comprises at least one first antistatic agent; and (iii)repeating (i) and (ii) at least once to form a core of athree-dimensional part.
 2. The method of claim 1 further comprising:(iv) applying a second fusing agent and a first detailing agent on thecore of the three-dimensional part to form an inner shell at leastpartially enclosing the core, wherein the first detailing agentcomprises at least one second antistatic agent; and (v) applying asecond detailing agent on the inner shell, wherein the second detailingagent is free of any near infrared absorbing compound.
 3. The method ofclaim 2, wherein: the first fusing agent further comprises a first nearinfrared absorbing compound; the second fusing agent further comprises asecond near infrared absorbing compound; and the second detailing agentfurther comprises at least one third antistatic agent.
 4. The method ofclaim 3, wherein: the first antistatic agent, the second antistaticagent, and the third antistatic agent are different; and the first nearinfrared absorbing compound and the second near infrared absorbingcompound are different.
 5. The method of claim 3, wherein: the firstantistatic agent, the second antistatic agent, and the third antistaticagent are the same, and the first antistatic agent, the secondantistatic agent, and the third antistatic agent are independentlyselected from the group consisting of Li₂NiBr₄, Li₂CuCl₄, LiCuO,LiCu₄O(PO₄)₂, LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂, LiN₃, C₆H₅COOLi, LiBr,Li₂CO₃, LiCl, C₆H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄, Li₃PO₄, Li₂SO₄, Li₂B₄O₇,LiAlCl₄, AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂, LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁,LiSVO, LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄, LiClO₄, LiCuS, LiPbCuS, LiFeS,LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂, LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅,lithium bis(oxalato)borate, LiN(SO₂CF₃)₂, LiN(SOCF₂CF₃)₂, LiAsF₆,LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃), LiN(SO₂F)(SO₂C₄F₉),LiOSO₂CF₃, and combinations thereof; and the first antistatic agent, thesecond antistatic agent, and the third antistatic agent areindependently selected from the group consisting of a salt of an alkalior alkaline earth metal selected from the group consisting of quaternaryamines, chlorates, phosphates, carbonates, borates, phosphonates,sulfates, acetates, citrates, perchlorates, and combinations thereof. 6.The method of claim 3, wherein: the first antistatic agent is present inan amount of from about 0.1 wt. % to about 10 wt. % based upon a totalweight of the first fusing agent; the second antistatic agent is presentin an amount of from about 0.01 wt. % to about 7 wt. % based upon atotal weight of the first detailing agent; and the third antistaticagent is present in an amount of from about 0.01 wt. % to about 7 wt. %based upon a total weight of the second detailing agent.
 7. The methodof claim 1, wherein the first fusing agent further comprises water, atleast one organic solvent, at least one surfactant, and at least onebiocide.
 8. A three-dimensional printed part comprising: a corecomprising: a build material selected from the group consisting ofpolyamides, polyethers, polyethylenes, polyethylene terephthalates,polystyrenes, polyacetals, polypropylenes, polycarbonates, polyesters,thermoplastic polyurethanes, and combinations thereof, at least onefirst antistatic agent an inner shell at least partially enclosing thecore, the inner shell comprising the build material and (i) at least onesecond antistatic agent or (ii) free of any antistatic agent; and anexternal shell at least partially enclosing the inner shell, theexternal shell comprising the build material and (i) at least one thirdantistatic agent or (ii) free of any antistatic agent.
 9. Thethree-dimensional printed part of claim 8, wherein the first antistaticagent, the second antistatic agent, and the third antistatic agent arethe same.
 10. The three-dimensional printed part of claim 8, wherein thefirst antistatic agent, the second antistatic agent, and thirdantistatic agent are thermally stable at a polymer melt processingtemperature.
 11. The three-dimensional printed part of claim 8, wherein:the first antistatic agent, the second antistatic agent, and the thirdantistatic agent are independently selected from the group consisting ofLi₂NiBr₄, Li₂CuCl₄, LiCuO, LiCu₄O(PO₄)₂, LiSOCl₂, LiSO₂Cl₂, LiSO₂, LiI₂,LiN₃, C₆H₅COOLi, LiBr, Li₂CO₃, LiCl, C₆H₁₁(CH₂)₃CO₂Li, LiBO₂, LiClO₄,Li₃PO₄, Li₂SO₄, Li₂B₄O₇, LiAlCl₄, AuCl₄Li, LiGaCl₄, LiBF₄, LiMnO₂,LiFeS₂, LiAg₂CrO₄, LiAg₂V₄O₁₁, LiSVO, LiCSVO, CF₃SO₃Li, LiPF₆, LiBF₄,LiClO₄, LiCuS, LiPbCuS, LiFeS, LiBi₂Pb₂O₅, LiBi₂O₃, LiV₂O₅, LiCoO₂,LiNiCoO₂, LiCuCl₂, Li/Al—V₂O₅, lithium bis(oxalato)borate, LiN(SO₂CF₃)₂,LiN(SOCF₂CF₃)₂, LiAsF₆, LiC(SO₂CF₃)₃, LiN(SO₂F)₂, LiN(SO₂F)(SO₂CF₃),LiN(SO₂F)(SO₂C₄F₉), LiOSO₂CF₃, and combinations thereof, or the firstantistatic agent, the second antistatic agent, and the third antistaticagent are independently selected from the group consisting of a salt ofan alkali or alkaline earth metal selected from the group consisting ofquaternary amines, chlorates, phosphates, carbonates, borates,phosphonates, sulfates, acetates, citrates, perchlorates, andcombinations thereof.
 12. The three-dimensional printed part of claim 8,wherein: the first antistatic agent is present in an amount of fromabout 0.1 wt. % to about 10 wt. % based upon a total weight of the core;the second antistatic agent is present in an amount of from about 0.01wt. % to about 7 wt. % based upon a total weight of the inner shell; andthe third antistatic agent is present in an amount of from about 0.01wt. % to about 7 wt. % based upon a total weight of the outer shell. 13.The three-dimensional printed part of claim 8, wherein the buildmaterial is polyamide-12, polyether block amide, or a combinationthereof.
 14. A method of three-dimensional printing comprising: (i)depositing a layer of build material; (ii) selectively applying a firstfusing agent comprising: at least one antistatic agent on the buildmaterial, at least one first near infrared absorbing compound, at leastone surfactant, at least one organic solvent, and water; (iii) repeating(i) and (ii) at least once to form a core of a three-dimensional part;(iv) applying a second fusing agent and a first detailing agent on thecore of the three-dimensional part to form an inner shell at leastpartially enclosing the core, wherein the second fusing agent comprisesat least one second near infrared absorbing compound, and wherein thefirst detailing agent is free of any antistatic agent; and (v) applyinga second detailing agent on the inner shell to at least partiallyenclose the inner shell and form an external shell, wherein the seconddetailing agent is free of (a) any near infrared absorbing compound and(b) any antistatic agent.